An example of a child safety seat was disclosed in EP 2 546 096 B1. The known child safety seat is mounted in the opposite direction to the direction of travel of the vehicle. By this means, in particular the head of the child may be better protected in the case of a sudden deceleration. In this prior art, it was additionally already proposed to equip at least individual parts of the seat shell, consisting of two side parts, a seat part, and a backrest part, with inflatable air chambers. For this purpose, in particular so-called drop stitch fabric was used in which two flat fabric pieces are arranged at a prespecified distance to one another using vertical threads. This embodiment has the advantage that the seat shell may have a high rigidity and form stability in the inflated state. On the other hand, the child safety seat may be easily transported in the non-inflated state. Finally, the weight may be reduced.
In practice, the insufficient stability of such child safety seats, on which high demands have been placed by the relevant regulatory authorities, has proven problematic up to now. An embodiment was disclosed in EP 2 546 096 B1, in which reinforcing straps were applied to the child safety seat. A first reinforcing strap was arranged on the outer side and a second reinforcing strap on the inner side of the child safety seat. The inner reinforcing strap was fastened on each side part at three fastening points. However, this embodiment includes the disadvantage that the force dissipation from the backrest part into the seat part is insufficient.
Such a child safety seat is additionally known from EP 2 502 780 A1.
U.S. Pat. No. 5,022,669 A discloses a child safety seat on which wheels are arranged on the underside so that the child safety seat is also usable as a child's pushchair.
The object of the invention is to resolve or to alleviate the disadvantages of the prior art. In particular, the goal of the invention is to improve the stability of the child safety seat of the type mentioned at the outset so that the peak forces acting on the child in the case of an impact of the vehicle are reduced.
This problem is solved by a child safety seat for fastening to a vehicle seat of a vehicle in the opposite direction of travel of the vehicle, the child safety seat comprising a backrest element, a first side element with a first inflatable air chamber, and a second side element with a second inflatable air chamber, wherein the first side element is connected to a first longitudinal edge of the backrest element and to a first longitudinal edge of the seat element, and the second element is connected to a second longitudinal edge of the backrest element and to a second longitudinal edge of the seat element.
According to the invention, a first tensile element is respectively connected to the first longitudinal edge of the backrest element and to the first longitudinal edge of the seat element, and a second tensile element is respectively connected to the second longitudinal edge of the backrest element and to the second longitudinal edge of the seat element, wherein the first tensile element and the second tensile element are arranged in a pretensioned state by the first and second side element.
By this means, a torque applied on the backrest element as a result of an impact of the vehicle may be reliably counteracted. The forces are dissipated from the backrest element directly into the seat element via the first and second tensile element, said seat element may be fastened using a seat belt (safety belt) to a vehicle seat in the opposite direction to the direction of travel. The first and second side elements are arranged on the backrest and seat elements such that the first and second tensile elements are tensioned in the inflated state of the first and second side elements, i.e., are under tension. Advantageously, it is not necessary in this embodiment to carry out a load dissipation via the first and second side elements, whose first and second air chambers are designed to be inflatable. For this purpose, a device for inflating the first and/or second air chambers may be provided. This device preferably has an inlet valve for introducing a filling gas. In contrast, the seat element and the backrest element are preferably free of an inflatable air chamber. The seat element and the backrest element each preferably have a higher weight per volume than the first and second side elements in the inflated state.
It is additionally preferred if the first and second side element are designed substantially identically.
In one preferred embodiment, the first and second side element each comprise a first flat fabric and a second flat fabric, which are connected to one another via vertical threads while leaving the first or second air chamber free (so-called drop stitch fabric). By this means, the first and second side elements are dimensionally stable and rigid in the inflated state.
For the purpose of this disclosure, the indications of location and direction, like “front”, “back”, “above”, “below”, “toward the front”, “toward the back” relate to the intended mounted state on the vehicle seat.
In order to stiffen the backrest element with respect to the seat element in the case of a frontal impact of the vehicle, it is advantageous if the first tensile element is respectively fastened to an upper end region of the first longitudinal edge of the backrest element and to a front end region of the first longitudinal edge of the seat element, wherein the second tensile element is respectively fastened to an upper end region of the second longitudinal edge of the backrest element and to a front end region of the second longitudinal edge of the seat element.
The stability of the child safety seat may be further improved if a third tensile element is respectively connected to the first longitudinal edge of the backrest element and to the first longitudinal edge of the seat element, and a fourth tensile element is respectively connected to the second longitudinal edge of the backrest element and to the second longitudinal edge of the seat element.
The first and second tensile elements may be connected to one another via a fifth tensile element and/or via a sixth tensile element. The fifth tensile element preferably extends in the region of an upper transverse edge of the backrest element. The sixth tensile element preferably extends in the region of a front transverse edge of the seat element. In this embodiment, the first, second, fifth, and/or sixth tensile elements may be designed as segments of an interconnected tensile element.
To transfer forces between the backrest element and the seat element, it is particularly favorable if the first and/or second and/or third and/or fourth tensile element is a traction cable, a traction belt, or a chain.
In order to be able to transfer the child safety seat in the non-inflated state of the first and second side elements into a compact transport position, it is advantageous if the backrest element comprises an upper backrest part and a lower backrest part, wherein the upper backrest part is connected to the lower backrest part via an articulated connection.
In order to stabilize the two-part backrest element against forces occurring during an accident, it is favorably if the one end of the third tensile element is fastened to an upper end region of the first longitudinal edge of the lower backrest part and the one end of the fourth tensile element is fastened to an upper end region of the second longitudinal edge of the lower backrest part, wherein the other end of the third tensile element is preferably fastened substantially at the center to the first longitudinal edge of the seat element and the other end of the fourth tensile element is preferably fastened substantially at the center to the second longitudinal edge of the seat element.
For stable fastening of the child safety seat to the vehicle seat, the seat element comprises according to a preferred embodiment a first and a second through opening for guiding through a belt segment of a safety belt. During the mounting of the child safety seat, the belt segment of the safety belt (seat belt) may be guided from below through the first through opening to the upper side of the seat element. Afterwards, the belt segment may be pulled substantially transversely to the seat element and guided through the second through opening, in order to finally connect a buckle tongue of the safety belt to a belt buckle.
For guiding the safety belt, the seat element preferably comprises a first deflection edge adjacent to the first through opening and a second deflection edge adjacent to the second through opening for the belt segment of the safety belt.
To facilitate a particularly effective force transfer from the backrest element to the seat element via the first, second, third, and fourth tensile elements, the first deflection edge of the seat element extends preferably between the fastening points of the first and third tensile elements on the first longitudinal edge of the seat element, when viewed in the longitudinal direction of the seat element, wherein the second deflection edge of the seat element extends between the fastening points of the second and fourth tensile elements on the second longitudinal edge of the seat element, when viewed in the longitudinal direction of the seat element.
In order to reliably apply the belt segment of the safety belt on the seat element, the first and/or the second deflection edge of the seat element may be flattened. The first and/or second deflection edge is respectively preferably arranged at an acute angle to the section to the seat element between the first and second through opening.
To facilitate the deflection of the belt segment on the seat element, the first and/or second through opening preferably comprises a section that widens in a direction away from a front edge of the seat element. Consequently, the opening width of the first and/or second through opening increases toward the rear (i.e., in the direction of the backrest element) in a top view. By this means, the first and/or second deflection edge is arranged at an angle to the first or second longitudinal edge of the seat element, so that the folding over of the belt segment of the safety belt is facilitated during mounting of the child safety seat to the vehicle seat.
In order to reliably hold the safety belt on the child safety seat in the secured state, a belt clamp for clamping at least one belt segment of the safety belt is preferably provided between the first and second through openings of the seat element when viewed in the transverse direction of the seat element.
With regard to a compact transport position of the child safety seat, it is provided in one preferred embodiment that the backrest element, in particular the lower backrest part of the backrest element, is preferably articulatedly connected to the seat element via a slip joint (or slide joint) or via a film hinge.
According to one preferred embodiment, the first side element comprises at least one first guide element on an inner side for guiding the first tensile element and/or at least one second guide element for guiding the third tensile element and/or the second side element comprises at least one third guide element on an inner side for guiding the second tensile element and/or the second side element comprises at least one fourth guide element on an inner side for guiding the fourth tensile element.
In order to provide a dimensionally stable seat shell, it is favorable if the seat element and/or the backrest element is manufactured substantially from a hard plastic material, in particular from polyamide or polypropylene, or from a fiber reinforced plastic material.
For force dissipation in the vehicle in the case of a rear impact, it is favorable if the first side element comprises a contact surface on a front face side for resting on a seat back of the vehicle seat in such a way that the upper end of the contact surface is arranged in the mounted state of the child safety seat at a distance of at least 170 mm to the lower end of the seat back when viewed in the longitudinal direction of the seat back.